6b0c312106
Add <limits.h> to the include files handled by "cache.h", and remove extraneous #include directives from various .c files. The rule is that "cache.h" gets all the basic stuff, so that we'll have as few system dependencies as possible.
610 lines
14 KiB
C
610 lines
14 KiB
C
/*
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* GIT - The information manager from hell
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*
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* Copyright (C) Linus Torvalds, 2005
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*
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* This handles basic git sha1 object files - packing, unpacking,
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* creation etc.
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*/
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#include "cache.h"
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#include "delta.h"
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#ifndef O_NOATIME
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#if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
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#define O_NOATIME 01000000
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#else
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#define O_NOATIME 0
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#endif
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#endif
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static unsigned int sha1_file_open_flag = O_NOATIME;
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static unsigned hexval(char c)
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{
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if (c >= '0' && c <= '9')
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return c - '0';
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if (c >= 'a' && c <= 'f')
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return c - 'a' + 10;
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if (c >= 'A' && c <= 'F')
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return c - 'A' + 10;
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return ~0;
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}
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int get_sha1_hex(const char *hex, unsigned char *sha1)
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{
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int i;
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for (i = 0; i < 20; i++) {
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unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
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if (val & ~0xff)
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return -1;
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*sha1++ = val;
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hex += 2;
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}
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return 0;
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}
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static int get_sha1_file(const char *path, unsigned char *result)
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{
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char buffer[60];
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int fd = open(path, O_RDONLY);
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int len;
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if (fd < 0)
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return -1;
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len = read(fd, buffer, sizeof(buffer));
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close(fd);
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if (len < 40)
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return -1;
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return get_sha1_hex(buffer, result);
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}
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static char *git_dir, *git_object_dir, *git_index_file;
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static void setup_git_env(void)
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{
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git_dir = gitenv(GIT_DIR_ENVIRONMENT);
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if (!git_dir)
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git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
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git_object_dir = gitenv(DB_ENVIRONMENT);
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if (!git_object_dir) {
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git_object_dir = xmalloc(strlen(git_dir) + 9);
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sprintf(git_object_dir, "%s/objects", git_dir);
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}
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git_index_file = gitenv(INDEX_ENVIRONMENT);
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if (!git_index_file) {
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git_index_file = xmalloc(strlen(git_dir) + 7);
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sprintf(git_index_file, "%s/index", git_dir);
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}
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}
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char *get_object_directory(void)
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{
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if (!git_object_dir)
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setup_git_env();
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return git_object_dir;
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}
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char *get_index_file(void)
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{
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if (!git_index_file)
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setup_git_env();
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return git_index_file;
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}
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int get_sha1(const char *str, unsigned char *sha1)
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{
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static char pathname[PATH_MAX];
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static const char *prefix[] = {
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"",
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"refs",
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"refs/tags",
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"refs/heads",
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"refs/snap",
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NULL
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};
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const char **p;
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if (!get_sha1_hex(str, sha1))
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return 0;
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if (!git_dir)
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setup_git_env();
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for (p = prefix; *p; p++) {
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snprintf(pathname, sizeof(pathname), "%s/%s/%s",
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git_dir, *p, str);
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if (!get_sha1_file(pathname, sha1))
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return 0;
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}
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return -1;
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}
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char * sha1_to_hex(const unsigned char *sha1)
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{
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static char buffer[50];
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static const char hex[] = "0123456789abcdef";
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char *buf = buffer;
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int i;
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for (i = 0; i < 20; i++) {
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unsigned int val = *sha1++;
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*buf++ = hex[val >> 4];
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*buf++ = hex[val & 0xf];
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}
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return buffer;
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}
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static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
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{
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int i;
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for (i = 0; i < 20; i++) {
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static char hex[] = "0123456789abcdef";
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unsigned int val = sha1[i];
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char *pos = pathbuf + i*2 + (i > 0);
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*pos++ = hex[val >> 4];
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*pos = hex[val & 0xf];
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}
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}
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/*
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* NOTE! This returns a statically allocated buffer, so you have to be
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* careful about using it. Do a "strdup()" if you need to save the
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* filename.
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*
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* Also note that this returns the location for creating. Reading
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* SHA1 file can happen from any alternate directory listed in the
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* DB_ENVIRONMENT environment variable if it is not found in
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* the primary object database.
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*/
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char *sha1_file_name(const unsigned char *sha1)
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{
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static char *name, *base;
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if (!base) {
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const char *sha1_file_directory = get_object_directory();
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int len = strlen(sha1_file_directory);
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base = xmalloc(len + 60);
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memcpy(base, sha1_file_directory, len);
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memset(base+len, 0, 60);
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base[len] = '/';
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base[len+3] = '/';
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name = base + len + 1;
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}
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fill_sha1_path(name, sha1);
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return base;
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}
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static struct alternate_object_database {
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char *base;
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char *name;
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} *alt_odb;
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/*
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* Prepare alternate object database registry.
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* alt_odb points at an array of struct alternate_object_database.
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* This array is terminated with an element that has both its base
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* and name set to NULL. alt_odb[n] comes from n'th non-empty
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* element from colon separated ALTERNATE_DB_ENVIRONMENT environment
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* variable, and its base points at a statically allocated buffer
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* that contains "/the/directory/corresponding/to/.git/objects/...",
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* while its name points just after the slash at the end of
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* ".git/objects/" in the example above, and has enough space to hold
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* 40-byte hex SHA1, an extra slash for the first level indirection,
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* and the terminating NUL.
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* This function allocates the alt_odb array and all the strings
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* pointed by base fields of the array elements with one xmalloc();
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* the string pool immediately follows the array.
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*/
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static void prepare_alt_odb(void)
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{
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int pass, totlen, i;
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const char *cp, *last;
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char *op = NULL;
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const char *alt = gitenv(ALTERNATE_DB_ENVIRONMENT) ? : "";
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/* The first pass counts how large an area to allocate to
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* hold the entire alt_odb structure, including array of
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* structs and path buffers for them. The second pass fills
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* the structure and prepares the path buffers for use by
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* fill_sha1_path().
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*/
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for (totlen = pass = 0; pass < 2; pass++) {
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last = alt;
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i = 0;
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do {
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cp = strchr(last, ':') ? : last + strlen(last);
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if (last != cp) {
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/* 43 = 40-byte + 2 '/' + terminating NUL */
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int pfxlen = cp - last;
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int entlen = pfxlen + 43;
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if (pass == 0)
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totlen += entlen;
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else {
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alt_odb[i].base = op;
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alt_odb[i].name = op + pfxlen + 1;
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memcpy(op, last, pfxlen);
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op[pfxlen] = op[pfxlen + 3] = '/';
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op[entlen-1] = 0;
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op += entlen;
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}
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i++;
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}
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while (*cp && *cp == ':')
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cp++;
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last = cp;
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} while (*cp);
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if (pass)
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break;
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alt_odb = xmalloc(sizeof(*alt_odb) * (i + 1) + totlen);
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alt_odb[i].base = alt_odb[i].name = NULL;
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op = (char*)(&alt_odb[i+1]);
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}
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}
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static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
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{
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int i;
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char *name = sha1_file_name(sha1);
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if (!stat(name, st))
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return name;
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if (!alt_odb)
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prepare_alt_odb();
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for (i = 0; (name = alt_odb[i].name) != NULL; i++) {
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fill_sha1_path(name, sha1);
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if (!stat(alt_odb[i].base, st))
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return alt_odb[i].base;
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}
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return NULL;
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}
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int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size, const char *type)
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{
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char header[100];
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unsigned char real_sha1[20];
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SHA_CTX c;
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SHA1_Init(&c);
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SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
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SHA1_Update(&c, map, size);
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SHA1_Final(real_sha1, &c);
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return memcmp(sha1, real_sha1, 20) ? -1 : 0;
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}
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void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
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{
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struct stat st;
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void *map;
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int fd;
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char *filename = find_sha1_file(sha1, &st);
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if (!filename) {
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error("cannot map sha1 file %s", sha1_to_hex(sha1));
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return NULL;
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}
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fd = open(filename, O_RDONLY | sha1_file_open_flag);
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if (fd < 0) {
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/* See if it works without O_NOATIME */
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switch (sha1_file_open_flag) {
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default:
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fd = open(filename, O_RDONLY);
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if (fd >= 0)
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break;
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/* Fallthrough */
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case 0:
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perror(filename);
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return NULL;
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}
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/* If it failed once, it will probably fail again. Stop using O_NOATIME */
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sha1_file_open_flag = 0;
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}
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map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
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close(fd);
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if (-1 == (int)(long)map)
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return NULL;
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*size = st.st_size;
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return map;
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}
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void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
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{
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int ret, bytes;
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z_stream stream;
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char buffer[8192];
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unsigned char *buf;
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/* Get the data stream */
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memset(&stream, 0, sizeof(stream));
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stream.next_in = map;
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stream.avail_in = mapsize;
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stream.next_out = (unsigned char *)buffer;
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stream.avail_out = sizeof(buffer);
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inflateInit(&stream);
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ret = inflate(&stream, 0);
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if (ret < Z_OK)
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return NULL;
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if (sscanf(buffer, "%10s %lu", type, size) != 2)
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return NULL;
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bytes = strlen(buffer) + 1;
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buf = xmalloc(*size);
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memcpy(buf, buffer + bytes, stream.total_out - bytes);
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bytes = stream.total_out - bytes;
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if (bytes < *size && ret == Z_OK) {
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stream.next_out = buf + bytes;
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stream.avail_out = *size - bytes;
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while (inflate(&stream, Z_FINISH) == Z_OK)
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/* nothing */;
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}
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inflateEnd(&stream);
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return buf;
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}
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void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
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{
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unsigned long mapsize;
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void *map, *buf;
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map = map_sha1_file(sha1, &mapsize);
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if (map) {
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buf = unpack_sha1_file(map, mapsize, type, size);
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munmap(map, mapsize);
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if (buf && !strcmp(type, "delta")) {
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void *ref = NULL, *delta = buf;
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unsigned long ref_size, delta_size = *size;
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buf = NULL;
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if (delta_size > 20)
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ref = read_sha1_file(delta, type, &ref_size);
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if (ref)
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buf = patch_delta(ref, ref_size,
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delta+20, delta_size-20,
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size);
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free(delta);
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free(ref);
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}
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return buf;
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}
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return NULL;
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}
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void *read_object_with_reference(const unsigned char *sha1,
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const char *required_type,
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unsigned long *size,
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unsigned char *actual_sha1_return)
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{
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char type[20];
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void *buffer;
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unsigned long isize;
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unsigned char actual_sha1[20];
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memcpy(actual_sha1, sha1, 20);
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while (1) {
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int ref_length = -1;
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const char *ref_type = NULL;
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buffer = read_sha1_file(actual_sha1, type, &isize);
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if (!buffer)
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return NULL;
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if (!strcmp(type, required_type)) {
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*size = isize;
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if (actual_sha1_return)
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memcpy(actual_sha1_return, actual_sha1, 20);
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return buffer;
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}
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/* Handle references */
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else if (!strcmp(type, "commit"))
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ref_type = "tree ";
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else if (!strcmp(type, "tag"))
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ref_type = "object ";
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else {
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free(buffer);
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return NULL;
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}
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ref_length = strlen(ref_type);
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if (memcmp(buffer, ref_type, ref_length) ||
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get_sha1_hex(buffer + ref_length, actual_sha1)) {
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free(buffer);
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return NULL;
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}
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/* Now we have the ID of the referred-to object in
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* actual_sha1. Check again. */
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}
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}
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int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
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{
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int size;
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unsigned char *compressed;
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z_stream stream;
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unsigned char sha1[20];
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SHA_CTX c;
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char *filename;
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static char tmpfile[PATH_MAX];
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unsigned char hdr[50];
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int fd, hdrlen, ret;
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/* Generate the header */
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hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
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/* Sha1.. */
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SHA1_Init(&c);
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SHA1_Update(&c, hdr, hdrlen);
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SHA1_Update(&c, buf, len);
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SHA1_Final(sha1, &c);
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if (returnsha1)
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memcpy(returnsha1, sha1, 20);
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filename = sha1_file_name(sha1);
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fd = open(filename, O_RDONLY);
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if (fd >= 0) {
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/*
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* FIXME!!! We might do collision checking here, but we'd
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* need to uncompress the old file and check it. Later.
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*/
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close(fd);
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return 0;
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}
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if (errno != ENOENT) {
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fprintf(stderr, "sha1 file %s: %s", filename, strerror(errno));
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return -1;
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}
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snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
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fd = mkstemp(tmpfile);
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if (fd < 0) {
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fprintf(stderr, "unable to create temporary sha1 filename %s: %s", tmpfile, strerror(errno));
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return -1;
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}
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/* Set it up */
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memset(&stream, 0, sizeof(stream));
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deflateInit(&stream, Z_BEST_COMPRESSION);
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size = deflateBound(&stream, len+hdrlen);
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compressed = xmalloc(size);
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/* Compress it */
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stream.next_out = compressed;
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stream.avail_out = size;
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/* First header.. */
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stream.next_in = hdr;
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stream.avail_in = hdrlen;
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while (deflate(&stream, 0) == Z_OK)
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/* nothing */;
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/* Then the data itself.. */
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stream.next_in = buf;
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stream.avail_in = len;
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while (deflate(&stream, Z_FINISH) == Z_OK)
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/* nothing */;
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deflateEnd(&stream);
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size = stream.total_out;
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if (write(fd, compressed, size) != size)
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die("unable to write file");
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fchmod(fd, 0444);
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close(fd);
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free(compressed);
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ret = link(tmpfile, filename);
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if (ret < 0) {
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ret = errno;
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/*
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* Coda hack - coda doesn't like cross-directory links,
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* so we fall back to a rename, which will mean that it
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* won't be able to check collisions, but that's not a
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* big deal.
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*
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* When this succeeds, we just return 0. We have nothing
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* left to unlink.
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*/
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if (ret == EXDEV && !rename(tmpfile, filename))
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return 0;
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}
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unlink(tmpfile);
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if (ret) {
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if (ret != EEXIST) {
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fprintf(stderr, "unable to write sha1 filename %s: %s", filename, strerror(ret));
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return -1;
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}
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/* FIXME!!! Collision check here ? */
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}
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return 0;
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}
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int write_sha1_from_fd(const unsigned char *sha1, int fd)
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{
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char *filename = sha1_file_name(sha1);
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int local;
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z_stream stream;
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unsigned char real_sha1[20];
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unsigned char buf[4096];
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unsigned char discard[4096];
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int ret;
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SHA_CTX c;
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local = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
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if (local < 0)
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return error("Couldn't open %s\n", filename);
|
|
|
|
memset(&stream, 0, sizeof(stream));
|
|
|
|
inflateInit(&stream);
|
|
|
|
SHA1_Init(&c);
|
|
|
|
do {
|
|
ssize_t size;
|
|
size = read(fd, buf, 4096);
|
|
if (size <= 0) {
|
|
close(local);
|
|
unlink(filename);
|
|
if (!size)
|
|
return error("Connection closed?");
|
|
perror("Reading from connection");
|
|
return -1;
|
|
}
|
|
write(local, buf, size);
|
|
stream.avail_in = size;
|
|
stream.next_in = buf;
|
|
do {
|
|
stream.next_out = discard;
|
|
stream.avail_out = sizeof(discard);
|
|
ret = inflate(&stream, Z_SYNC_FLUSH);
|
|
SHA1_Update(&c, discard, sizeof(discard) -
|
|
stream.avail_out);
|
|
} while (stream.avail_in && ret == Z_OK);
|
|
|
|
} while (ret == Z_OK);
|
|
inflateEnd(&stream);
|
|
|
|
close(local);
|
|
SHA1_Final(real_sha1, &c);
|
|
if (ret != Z_STREAM_END) {
|
|
unlink(filename);
|
|
return error("File %s corrupted", sha1_to_hex(sha1));
|
|
}
|
|
if (memcmp(sha1, real_sha1, 20)) {
|
|
unlink(filename);
|
|
return error("File %s has bad hash\n", sha1_to_hex(sha1));
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int has_sha1_file(const unsigned char *sha1)
|
|
{
|
|
struct stat st;
|
|
return !!find_sha1_file(sha1, &st);
|
|
}
|
|
|
|
int index_fd(unsigned char *sha1, int fd, struct stat *st)
|
|
{
|
|
unsigned long size = st->st_size;
|
|
void *buf;
|
|
int ret;
|
|
|
|
buf = "";
|
|
if (size)
|
|
buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
|
|
close(fd);
|
|
if ((int)(long)buf == -1)
|
|
return -1;
|
|
|
|
ret = write_sha1_file(buf, size, "blob", sha1);
|
|
if (size)
|
|
munmap(buf, size);
|
|
return ret;
|
|
}
|