758787061
Denis Vlasenko
2007-07-27
Subject
dd: fix bug where we assume count=INT_MAX when count is unspecified; shrink dd while at it
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coreutils/dd.c+53 -32
| @@ -32,6 +32,9 @@ struct globals { | |
| off_t out_full, out_part, in_full, in_part; | |
| }; | |
| #define G (*(struct globals*)&bb_common_bufsiz1) | |
| + | /* We have to zero it out because of NOEXEC */ |
| + | #define INIT_G() memset(&G, 0, sizeof(G)) |
| + | |
| static void dd_output_status(int ATTRIBUTE_UNUSED cur_signal) | |
| { | |
| @@ -73,10 +76,11 @@ int dd_main(int argc, char **argv); | |
| int dd_main(int argc, char **argv) | |
| { | |
| enum { | |
| - | SYNC_FLAG = 1 << 0, |
| - | NOERROR = 1 << 1, |
| - | TRUNC_FLAG = 1 << 2, |
| - | TWOBUFS_FLAG = 1 << 3, |
| + | FLAG_SYNC = 1 << 0, |
| + | FLAG_NOERROR = 1 << 1, |
| + | FLAG_NOTRUNC = 1 << 2, |
| + | FLAG_TWOBUFS = 1 << 3, |
| + | FLAG_COUNT = 1 << 4, |
| }; | |
| static const char keywords[] = | |
| "bs=\0""count=\0""seek=\0""skip=\0""if=\0""of=\0" | |
| @@ -100,25 +104,41 @@ int dd_main(int argc, char **argv) | |
| OP_conv_noerror, | |
| #endif | |
| }; | |
| - | int flags = TRUNC_FLAG; |
| - | size_t oc = 0, ibs = 512, obs = 512; |
| + | size_t ibs = 512, obs = 512; |
| ssize_t n, w; | |
| - | off_t seek = 0, skip = 0, count = OFF_T_MAX; |
| - | int ifd, ofd; |
| - | const char *infile = NULL, *outfile = NULL; |
| char *ibuf, *obuf; | |
| + | /* And these are all zeroed at once! */ |
| + | struct { |
| + | int flags; |
| + | int ifd, ofd; |
| + | size_t oc; |
| + | off_t count; |
| + | off_t seek, skip; |
| + | const char *infile, *outfile; |
| + | #if ENABLE_FEATURE_DD_SIGNAL_HANDLING |
| + | struct sigaction sigact; |
| + | #endif |
| + | } Z; |
| + | #define flags (Z.flags ) |
| + | #define ifd (Z.ifd ) |
| + | #define ofd (Z.ofd ) |
| + | #define oc (Z.oc ) |
| + | #define count (Z.count ) |
| + | #define seek (Z.seek ) |
| + | #define skip (Z.skip ) |
| + | #define infile (Z.infile ) |
| + | #define outfile (Z.outfile) |
| + | #define sigact (Z.sigact ) |
| - | memset(&G, 0, sizeof(G)); /* because of NOEXEC */ |
| - | |
| - | if (ENABLE_FEATURE_DD_SIGNAL_HANDLING) { |
| - | struct sigaction sa; |
| + | memset(&Z, 0, sizeof(Z)); |
| + | INIT_G(); |
| - | memset(&sa, 0, sizeof(sa)); |
| - | sa.sa_handler = dd_output_status; |
| - | sa.sa_flags = SA_RESTART; |
| - | sigemptyset(&sa.sa_mask); |
| - | sigaction(SIGUSR1, &sa, 0); |
| - | } |
| + | #if ENABLE_FEATURE_DD_SIGNAL_HANDLING |
| + | sigact.sa_handler = dd_output_status; |
| + | sigact.sa_flags = SA_RESTART; |
| + | sigemptyset(&sigact.sa_mask); |
| + | sigaction(SIGUSR1, &sigact, NULL); |
| + | #endif |
| for (n = 1; n < argc; n++) { | |
| smalluint key_len; | |
| @@ -162,11 +182,11 @@ int dd_main(int argc, char **argv) | |
| if (what < OP_conv_notrunc) | |
| bb_error_msg_and_die(bb_msg_invalid_arg, arg, "conv"); | |
| if (what == OP_conv_notrunc) | |
| - | flags &= ~TRUNC_FLAG; |
| + | flags |= FLAG_NOTRUNC; |
| if (what == OP_conv_sync) | |
| - | flags |= SYNC_FLAG; |
| + | flags |= FLAG_SYNC; |
| if (what == OP_conv_noerror) | |
| - | flags |= NOERROR; |
| + | flags |= FLAG_NOERROR; |
| if (!key) /* no ',' left, so this was the last specifier */ | |
| break; | |
| arg = key + 1; /* skip this keyword and ',' */ | |
| @@ -180,6 +200,7 @@ int dd_main(int argc, char **argv) | |
| } | |
| /* These can be large: */ | |
| if (what == OP_count) { | |
| + | flags |= FLAG_COUNT; |
| count = XATOU_SFX(arg, dd_suffixes); | |
| continue; | |
| } | |
| @@ -201,24 +222,24 @@ int dd_main(int argc, char **argv) | |
| //XXX:FIXME for huge ibs or obs, malloc'ing them isn't the brightest idea ever | |
| ibuf = obuf = xmalloc(ibs); | |
| if (ibs != obs) { | |
| - | flags |= TWOBUFS_FLAG; |
| + | flags |= FLAG_TWOBUFS; |
| obuf = xmalloc(obs); | |
| } | |
| if (infile != NULL) | |
| ifd = xopen(infile, O_RDONLY); | |
| else { | |
| - | ifd = STDIN_FILENO; |
| + | /* ifd = STDIN_FILENO; - it's zero and it's already there */ |
| infile = bb_msg_standard_input; | |
| } | |
| if (outfile != NULL) { | |
| int oflag = O_WRONLY | O_CREAT; | |
| - | if (!seek && (flags & TRUNC_FLAG)) |
| + | if (!seek && !(flags & FLAG_NOTRUNC)) |
| oflag |= O_TRUNC; | |
| ofd = xopen(outfile, oflag); | |
| - | if (seek && (flags & TRUNC_FLAG)) { |
| + | if (seek && !(flags & FLAG_NOTRUNC)) { |
| if (ftruncate(ofd, seek * obs) < 0) { | |
| struct stat st; | |
| @@ -247,14 +268,14 @@ int dd_main(int argc, char **argv) | |
| goto die_outfile; | |
| } | |
| - | while (G.in_full + G.in_part != count) { |
| - | if (flags & NOERROR) /* Pre-zero the buffer when for NOERROR */ |
| - | memset(ibuf, '\0', ibs); |
| + | while ((flags & FLAG_COUNT) && (G.in_full + G.in_part != count)) { |
| + | if (flags & FLAG_NOERROR) /* Pre-zero the buffer if conv=noerror */ |
| + | memset(ibuf, 0, ibs); |
| n = safe_read(ifd, ibuf, ibs); | |
| if (n == 0) | |
| break; | |
| if (n < 0) { | |
| - | if (flags & NOERROR) { |
| + | if (flags & FLAG_NOERROR) { |
| n = ibs; | |
| bb_perror_msg("%s", infile); | |
| } else | |
| @@ -264,12 +285,12 @@ int dd_main(int argc, char **argv) | |
| G.in_full++; | |
| else { | |
| G.in_part++; | |
| - | if (flags & SYNC_FLAG) { |
| + | if (flags & FLAG_SYNC) { |
| memset(ibuf + n, '\0', ibs - n); | |
| n = ibs; | |
| } | |
| } | |
| - | if (flags & TWOBUFS_FLAG) { |
| + | if (flags & FLAG_TWOBUFS) { |
| char *tmp = ibuf; | |
| while (n) { | |
| size_t d = obs - oc; | |