diff options
Diffstat (limited to 'sha1_file.c')
| -rw-r--r-- | sha1_file.c | 171 |
1 files changed, 149 insertions, 22 deletions
diff --git a/sha1_file.c b/sha1_file.c index e21f4b3..942b673 100644 --- a/sha1_file.c +++ b/sha1_file.c @@ -7,6 +7,7 @@ * creation etc. */ #include <stdarg.h> +#include <limits.h> #include "cache.h" #ifndef O_NOATIME @@ -58,6 +59,38 @@ int get_sha1_file(const char *path, unsigned char *result) return get_sha1_hex(buffer, result); } +static char *git_dir, *git_object_dir, *git_index_file; +static void setup_git_env(void) +{ + git_dir = gitenv(GIT_DIR_ENVIRONMENT); + if (!git_dir) + git_dir = DEFAULT_GIT_DIR_ENVIRONMENT; + git_object_dir = gitenv(DB_ENVIRONMENT); + if (!git_object_dir) { + git_object_dir = xmalloc(strlen(git_dir) + 9); + sprintf(git_object_dir, "%s/objects", git_dir); + } + git_index_file = gitenv(INDEX_ENVIRONMENT); + if (!git_index_file) { + git_index_file = xmalloc(strlen(git_dir) + 7); + sprintf(git_index_file, "%s/index", git_dir); + } +} + +char *get_object_directory(void) +{ + if (!git_object_dir) + setup_git_env(); + return git_object_dir; +} + +char *get_index_file(void) +{ + if (!git_index_file) + setup_git_env(); + return git_index_file; +} + int get_sha1(const char *str, unsigned char *sha1) { static char pathname[PATH_MAX]; @@ -69,15 +102,16 @@ int get_sha1(const char *str, unsigned char *sha1) "refs/snap", NULL }; - const char *gitdir; const char **p; if (!get_sha1_hex(str, sha1)) return 0; - gitdir = ".git"; + if (!git_dir) + setup_git_env(); for (p = prefix; *p; p++) { - snprintf(pathname, sizeof(pathname), "%s/%s/%s", gitdir, *p, str); + snprintf(pathname, sizeof(pathname), "%s/%s/%s", + git_dir, *p, str); if (!get_sha1_file(pathname, sha1)) return 0; } @@ -100,18 +134,34 @@ char * sha1_to_hex(const unsigned char *sha1) return buffer; } +static void fill_sha1_path(char *pathbuf, const unsigned char *sha1) +{ + int i; + for (i = 0; i < 20; i++) { + static char hex[] = "0123456789abcdef"; + unsigned int val = sha1[i]; + char *pos = pathbuf + i*2 + (i > 0); + *pos++ = hex[val >> 4]; + *pos = hex[val & 0xf]; + } +} + /* * NOTE! This returns a statically allocated buffer, so you have to be * careful about using it. Do a "strdup()" if you need to save the * filename. + * + * Also note that this returns the location for creating. Reading + * SHA1 file can happen from any alternate directory listed in the + * DB_ENVIRONMENT environment variable if it is not found in + * the primary object database. */ char *sha1_file_name(const unsigned char *sha1) { - int i; static char *name, *base; if (!base) { - char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT; + const char *sha1_file_directory = get_object_directory(); int len = strlen(sha1_file_directory); base = xmalloc(len + 60); memcpy(base, sha1_file_directory, len); @@ -120,16 +170,94 @@ char *sha1_file_name(const unsigned char *sha1) base[len+3] = '/'; name = base + len + 1; } - for (i = 0; i < 20; i++) { - static char hex[] = "0123456789abcdef"; - unsigned int val = sha1[i]; - char *pos = name + i*2 + (i > 0); - *pos++ = hex[val >> 4]; - *pos = hex[val & 0xf]; - } + fill_sha1_path(name, sha1); return base; } +static struct alternate_object_database { + char *base; + char *name; +} *alt_odb; + +/* + * Prepare alternate object database registry. + * alt_odb points at an array of struct alternate_object_database. + * This array is terminated with an element that has both its base + * and name set to NULL. alt_odb[n] comes from n'th non-empty + * element from colon separated ALTERNATE_DB_ENVIRONMENT environment + * variable, and its base points at a statically allocated buffer + * that contains "/the/directory/corresponding/to/.git/objects/...", + * while its name points just after the slash at the end of + * ".git/objects/" in the example above, and has enough space to hold + * 40-byte hex SHA1, an extra slash for the first level indirection, + * and the terminating NUL. + * This function allocates the alt_odb array and all the strings + * pointed by base fields of the array elements with one xmalloc(); + * the string pool immediately follows the array. + */ +static void prepare_alt_odb(void) +{ + int pass, totlen, i; + const char *cp, *last; + char *op = 0; + const char *alt = gitenv(ALTERNATE_DB_ENVIRONMENT) ? : ""; + + /* The first pass counts how large an area to allocate to + * hold the entire alt_odb structure, including array of + * structs and path buffers for them. The second pass fills + * the structure and prepares the path buffers for use by + * fill_sha1_path(). + */ + for (totlen = pass = 0; pass < 2; pass++) { + last = alt; + i = 0; + do { + cp = strchr(last, ':') ? : last + strlen(last); + if (last != cp) { + /* 43 = 40-byte + 2 '/' + terminating NUL */ + int pfxlen = cp - last; + int entlen = pfxlen + 43; + if (pass == 0) + totlen += entlen; + else { + alt_odb[i].base = op; + alt_odb[i].name = op + pfxlen + 1; + memcpy(op, last, pfxlen); + op[pfxlen] = op[pfxlen + 3] = '/'; + op[entlen-1] = 0; + op += entlen; + } + i++; + } + while (*cp && *cp == ':') + cp++; + last = cp; + } while (*cp); + if (pass) + break; + alt_odb = xmalloc(sizeof(*alt_odb) * (i + 1) + totlen); + alt_odb[i].base = alt_odb[i].name = 0; + op = (char*)(&alt_odb[i+1]); + } +} + +static char *find_sha1_file(const unsigned char *sha1, struct stat *st) +{ + int i; + char *name = sha1_file_name(sha1); + + if (!stat(name, st)) + return name; + if (!alt_odb) + prepare_alt_odb(); + for (i = 0; (name = alt_odb[i].name) != NULL; i++) { + fill_sha1_path(name, sha1); + if (!stat(alt_odb[i].base, st)) + return alt_odb[i].base; + } + return NULL; +} + int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size, const char *type) { char header[100]; @@ -145,10 +273,15 @@ int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size, con void *map_sha1_file(const unsigned char *sha1, unsigned long *size) { - char *filename = sha1_file_name(sha1); struct stat st; void *map; int fd; + char *filename = find_sha1_file(sha1, &st); + + if (!filename) { + error("cannot map sha1 file %s", sha1_to_hex(sha1)); + return NULL; + } fd = open(filename, O_RDONLY | sha1_file_open_flag); if (fd < 0) { @@ -167,10 +300,6 @@ void *map_sha1_file(const unsigned char *sha1, unsigned long *size) /* If it failed once, it will probably fail again. Stop using O_NOATIME */ sha1_file_open_flag = 0; } - if (fstat(fd, &st) < 0) { - close(fd); - return NULL; - } map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); close(fd); if (-1 == (int)(long)map) @@ -315,6 +444,7 @@ int write_sha1_file(char *buf, unsigned long len, const char *type, unsigned cha } snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory()); + fd = mkstemp(tmpfile); if (fd < 0) { fprintf(stderr, "unable to create temporary sha1 filename %s: %s", tmpfile, strerror(errno)); @@ -349,6 +479,7 @@ int write_sha1_file(char *buf, unsigned long len, const char *type, unsigned cha die("unable to write file"); fchmod(fd, 0444); close(fd); + free(compressed); ret = link(tmpfile, filename); if (ret < 0) { @@ -442,12 +573,8 @@ int write_sha1_from_fd(const unsigned char *sha1, int fd) int has_sha1_file(const unsigned char *sha1) { - char *filename = sha1_file_name(sha1); struct stat st; - - if (!stat(filename, &st)) - return 1; - return 0; + return !!find_sha1_file(sha1, &st); } int index_fd(unsigned char *sha1, int fd, struct stat *st) |