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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-18 20:04:43 (GMT)
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-18 20:04:43 (GMT)
commit0fcfd160b0495c0881e142c546c4418b8cea7e93 (patch)
tree21bdf6702f0dfe75fc7caa3882da7bb34b0bc4bf /sha1_file.c
parent0a02ce72d9ab78d061b2cc919bc15e36fe620ddc (diff)
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Split up read-cache.c into more logical clumps.
Do the usage and error reporting in "usage.c", and the sha1 file accesses in "sha1_file.c". Small, nice, easily separated parts. Good.
Diffstat (limited to 'sha1_file.c')
-rw-r--r--sha1_file.c247
1 files changed, 247 insertions, 0 deletions
diff --git a/sha1_file.c b/sha1_file.c
new file mode 100644
index 0000000..bb44a01
--- /dev/null
+++ b/sha1_file.c
@@ -0,0 +1,247 @@
+/*
+ * GIT - The information manager from hell
+ *
+ * Copyright (C) Linus Torvalds, 2005
+ *
+ * This handles basic git sha1 object files - packing, unpacking,
+ * creation etc.
+ */
+#include <stdarg.h>
+#include "cache.h"
+
+const char *sha1_file_directory = NULL;
+
+static unsigned hexval(char c)
+{
+ if (c >= '0' && c <= '9')
+ return c - '0';
+ if (c >= 'a' && c <= 'f')
+ return c - 'a' + 10;
+ if (c >= 'A' && c <= 'F')
+ return c - 'A' + 10;
+ return ~0;
+}
+
+int get_sha1_hex(const char *hex, unsigned char *sha1)
+{
+ int i;
+ for (i = 0; i < 20; i++) {
+ unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
+ if (val & ~0xff)
+ return -1;
+ *sha1++ = val;
+ hex += 2;
+ }
+ return 0;
+}
+
+char * sha1_to_hex(const unsigned char *sha1)
+{
+ static char buffer[50];
+ static const char hex[] = "0123456789abcdef";
+ char *buf = buffer;
+ int i;
+
+ for (i = 0; i < 20; i++) {
+ unsigned int val = *sha1++;
+ *buf++ = hex[val >> 4];
+ *buf++ = hex[val & 0xf];
+ }
+ return buffer;
+}
+
+/*
+ * 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.
+ */
+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;
+ int len = strlen(sha1_file_directory);
+ base = malloc(len + 60);
+ memcpy(base, sha1_file_directory, len);
+ memset(base+len, 0, 60);
+ base[len] = '/';
+ 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];
+ }
+ return base;
+}
+
+int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size)
+{
+ unsigned char real_sha1[20];
+ SHA_CTX c;
+
+ SHA1_Init(&c);
+ SHA1_Update(&c, map, size);
+ SHA1_Final(real_sha1, &c);
+ return memcmp(sha1, real_sha1, 20) ? -1 : 0;
+}
+
+void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
+{
+ char *filename = sha1_file_name(sha1);
+ int fd = open(filename, O_RDONLY);
+ struct stat st;
+ void *map;
+
+ if (fd < 0) {
+ perror(filename);
+ return NULL;
+ }
+ 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)
+ return NULL;
+ *size = st.st_size;
+ return map;
+}
+
+void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
+{
+ int ret, bytes;
+ z_stream stream;
+ char buffer[8192];
+ char *buf;
+
+ /* Get the data stream */
+ memset(&stream, 0, sizeof(stream));
+ stream.next_in = map;
+ stream.avail_in = mapsize;
+ stream.next_out = buffer;
+ stream.avail_out = sizeof(buffer);
+
+ inflateInit(&stream);
+ ret = inflate(&stream, 0);
+ if (sscanf(buffer, "%10s %lu", type, size) != 2)
+ return NULL;
+
+ bytes = strlen(buffer) + 1;
+ buf = malloc(*size);
+ if (!buf)
+ return NULL;
+
+ memcpy(buf, buffer + bytes, stream.total_out - bytes);
+ bytes = stream.total_out - bytes;
+ if (bytes < *size && ret == Z_OK) {
+ stream.next_out = buf + bytes;
+ stream.avail_out = *size - bytes;
+ while (inflate(&stream, Z_FINISH) == Z_OK)
+ /* nothing */;
+ }
+ inflateEnd(&stream);
+ return buf;
+}
+
+void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
+{
+ unsigned long mapsize;
+ void *map, *buf;
+
+ map = map_sha1_file(sha1, &mapsize);
+ if (map) {
+ buf = unpack_sha1_file(map, mapsize, type, size);
+ munmap(map, mapsize);
+ return buf;
+ }
+ return NULL;
+}
+
+int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1)
+{
+ int size;
+ char *compressed;
+ z_stream stream;
+ unsigned char sha1[20];
+ SHA_CTX c;
+
+ /* Set it up */
+ memset(&stream, 0, sizeof(stream));
+ deflateInit(&stream, Z_BEST_COMPRESSION);
+ size = deflateBound(&stream, len);
+ compressed = malloc(size);
+
+ /* Compress it */
+ stream.next_in = buf;
+ stream.avail_in = len;
+ stream.next_out = compressed;
+ stream.avail_out = size;
+ while (deflate(&stream, Z_FINISH) == Z_OK)
+ /* nothing */;
+ deflateEnd(&stream);
+ size = stream.total_out;
+
+ /* Sha1.. */
+ SHA1_Init(&c);
+ SHA1_Update(&c, compressed, size);
+ SHA1_Final(sha1, &c);
+
+ if (write_sha1_buffer(sha1, compressed, size) < 0)
+ return -1;
+ if (returnsha1)
+ memcpy(returnsha1, sha1, 20);
+ return 0;
+}
+
+static inline int collision_check(char *filename, void *buf, unsigned int size)
+{
+#ifdef COLLISION_CHECK
+ void *map;
+ int fd = open(filename, O_RDONLY);
+ struct stat st;
+ int cmp;
+
+ /* Unreadable object, or object went away? Strange. */
+ if (fd < 0)
+ return -1;
+
+ if (fstat(fd, &st) < 0 || size != st.st_size)
+ return -1;
+
+ map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
+ close(fd);
+ if (map == MAP_FAILED)
+ return -1;
+ cmp = memcmp(buf, map, size);
+ munmap(map, size);
+ if (cmp)
+ return -1;
+#endif
+ return 0;
+}
+
+int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size)
+{
+ char *filename = sha1_file_name(sha1);
+ int fd;
+
+ fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
+ if (fd < 0) {
+ if (errno != EEXIST)
+ return -1;
+ if (collision_check(filename, buf, size))
+ return error("SHA1 collision detected!"
+ " This is bad, bad, BAD!\a\n");
+ return 0;
+ }
+ write(fd, buf, size);
+ close(fd);
+ return 0;
+}