in src/client/mac/handler/breakpad_nlist_64.cc [171:402]
int __breakpad_fdnlist(int fd, nlist_type *list, const char **symbolNames,
cpu_type_t cpu_type) {
typedef typename MachBits<nlist_type>::mach_header_type mach_header_type;
typedef typename MachBits<nlist_type>::word_type word_type;
const uint32_t magic = MachBits<nlist_type>::magic;
int maxlen = 500;
int nreq = 0;
for (nlist_type* q = list;
symbolNames[q-list] && symbolNames[q-list][0];
q++, nreq++) {
q->n_type = 0;
q->n_value = 0;
q->n_desc = 0;
q->n_sect = 0;
q->n_un.n_strx = 0;
}
struct exec buf;
if (read(fd, (char *)&buf, sizeof(buf)) != sizeof(buf) ||
(N_BADMAG(buf) && *((uint32_t *)&buf) != magic &&
CFSwapInt32BigToHost(*((uint32_t *)&buf)) != FAT_MAGIC &&
/* The following is the big-endian ppc64 check */
(*((uint32_t*)&buf)) != FAT_MAGIC)) {
return -1;
}
/* Deal with fat file if necessary */
unsigned arch_offset = 0;
if (CFSwapInt32BigToHost(*((uint32_t *)&buf)) == FAT_MAGIC ||
/* The following is the big-endian ppc64 check */
*((unsigned int *)&buf) == FAT_MAGIC) {
/* Read in the fat header */
struct fat_header fh;
if (lseek(fd, 0, SEEK_SET) == -1) {
return -1;
}
if (read(fd, (char *)&fh, sizeof(fh)) != sizeof(fh)) {
return -1;
}
/* Convert fat_narchs to host byte order */
fh.nfat_arch = CFSwapInt32BigToHost(fh.nfat_arch);
/* Read in the fat archs */
struct fat_arch *fat_archs =
(struct fat_arch *)malloc(fh.nfat_arch * sizeof(struct fat_arch));
if (fat_archs == NULL) {
return -1;
}
if (read(fd, (char *)fat_archs,
sizeof(struct fat_arch) * fh.nfat_arch) !=
(ssize_t)(sizeof(struct fat_arch) * fh.nfat_arch)) {
free(fat_archs);
return -1;
}
/*
* Convert archs to host byte ordering (a constraint of
* cpusubtype_getbestarch()
*/
for (unsigned i = 0; i < fh.nfat_arch; i++) {
fat_archs[i].cputype =
CFSwapInt32BigToHost(fat_archs[i].cputype);
fat_archs[i].cpusubtype =
CFSwapInt32BigToHost(fat_archs[i].cpusubtype);
fat_archs[i].offset =
CFSwapInt32BigToHost(fat_archs[i].offset);
fat_archs[i].size =
CFSwapInt32BigToHost(fat_archs[i].size);
fat_archs[i].align =
CFSwapInt32BigToHost(fat_archs[i].align);
}
struct fat_arch *fap = NULL;
for (unsigned i = 0; i < fh.nfat_arch; i++) {
if (fat_archs[i].cputype == cpu_type) {
fap = &fat_archs[i];
break;
}
}
if (!fap) {
free(fat_archs);
return -1;
}
arch_offset = fap->offset;
free(fat_archs);
/* Read in the beginning of the architecture-specific file */
if (lseek(fd, arch_offset, SEEK_SET) == -1) {
return -1;
}
if (read(fd, (char *)&buf, sizeof(buf)) != sizeof(buf)) {
return -1;
}
}
off_t sa; /* symbol address */
off_t ss; /* start of strings */
register_t n;
if (*((unsigned int *)&buf) == magic) {
if (lseek(fd, arch_offset, SEEK_SET) == -1) {
return -1;
}
mach_header_type mh;
if (read(fd, (char *)&mh, sizeof(mh)) != sizeof(mh)) {
return -1;
}
struct load_command *load_commands =
(struct load_command *)malloc(mh.sizeofcmds);
if (load_commands == NULL) {
return -1;
}
if (read(fd, (char *)load_commands, mh.sizeofcmds) !=
(ssize_t)mh.sizeofcmds) {
free(load_commands);
return -1;
}
struct symtab_command *stp = NULL;
struct load_command *lcp = load_commands;
// iterate through all load commands, looking for
// LC_SYMTAB load command
for (uint32_t i = 0; i < mh.ncmds; i++) {
if (lcp->cmdsize % sizeof(word_type) != 0 ||
lcp->cmdsize <= 0 ||
(char *)lcp + lcp->cmdsize >
(char *)load_commands + mh.sizeofcmds) {
free(load_commands);
return -1;
}
if (lcp->cmd == LC_SYMTAB) {
if (lcp->cmdsize !=
sizeof(struct symtab_command)) {
free(load_commands);
return -1;
}
stp = (struct symtab_command *)lcp;
break;
}
lcp = (struct load_command *)
((char *)lcp + lcp->cmdsize);
}
if (stp == NULL) {
free(load_commands);
return -1;
}
// sa points to the beginning of the symbol table
sa = stp->symoff + arch_offset;
// ss points to the beginning of the string table
ss = stp->stroff + arch_offset;
// n is the number of bytes in the symbol table
// each symbol table entry is an nlist structure
n = stp->nsyms * sizeof(nlist_type);
free(load_commands);
} else {
sa = N_SYMOFF(buf) + arch_offset;
ss = sa + buf.a_syms + arch_offset;
n = buf.a_syms;
}
if (lseek(fd, sa, SEEK_SET) == -1) {
return -1;
}
// the algorithm here is to read the nlist entries in m-sized
// chunks into q. q is then iterated over. for each entry in q,
// use the string table index(q->n_un.n_strx) to read the symbol
// name, then scan the nlist entries passed in by the user(via p),
// and look for a match
while (n) {
nlist_type space[BUFSIZ/sizeof (nlist_type)];
register_t m = sizeof (space);
if (n < m)
m = n;
if (read(fd, (char *)space, m) != m)
break;
n -= m;
off_t savpos = lseek(fd, 0, SEEK_CUR);
if (savpos == -1) {
return -1;
}
for (nlist_type* q = space; (m -= sizeof(nlist_type)) >= 0; q++) {
char nambuf[BUFSIZ];
if (q->n_un.n_strx == 0 || q->n_type & N_STAB)
continue;
// seek to the location in the binary where the symbol
// name is stored & read it into memory
if (lseek(fd, ss+q->n_un.n_strx, SEEK_SET) == -1) {
return -1;
}
if (read(fd, nambuf, maxlen+1) == -1) {
return -1;
}
const char *s2 = nambuf;
for (nlist_type *p = list;
symbolNames[p-list] && symbolNames[p-list][0];
p++) {
// get the symbol name the user has passed in that
// corresponds to the nlist entry that we're looking at
const char *s1 = symbolNames[p - list];
while (*s1) {
if (*s1++ != *s2++)
goto cont;
}
if (*s2)
goto cont;
p->n_value = q->n_value;
p->n_type = q->n_type;
p->n_desc = q->n_desc;
p->n_sect = q->n_sect;
p->n_un.n_strx = q->n_un.n_strx;
if (--nreq == 0)
return nreq;
break;
cont: ;
}
}
if (lseek(fd, savpos, SEEK_SET) == -1) {
return -1;
}
}
return nreq;
}