From 86928dfb6f6a76bb2762afcef2dc0a2922b7b2bf Mon Sep 17 00:00:00 2001 From: Gerd Moellmann Date: Sat, 10 Nov 2001 11:40:04 +0000 Subject: [PATCH] (unexec): Use mmap/munmap to allocate buffers instead of malloc/free. --- src/ChangeLog | 5 +++++ src/unexelf.c | 32 ++++++++++++++------------------ 2 files changed, 19 insertions(+), 18 deletions(-) diff --git a/src/ChangeLog b/src/ChangeLog index 4ac5ee52967..0a19005c33f 100644 --- a/src/ChangeLog +++ b/src/ChangeLog @@ -1,3 +1,8 @@ +2001-11-10 Gerd Moellmann + + * unexelf.c (unexec): Use mmap/munmap to allocate buffers + instead of malloc/free. + 2001-11-09 Pavel Jan,Bm(Bk * xfaces.c (merge_face_vectors): Use braces to follow GNU diff --git a/src/unexelf.c b/src/unexelf.c index 222de55ed56..8ea893e532f 100644 --- a/src/unexelf.c +++ b/src/unexelf.c @@ -668,6 +668,7 @@ unexec (new_name, old_name, data_start, bss_start, entry_address) int old_data_index, new_data2_index; int old_mdebug_index; struct stat stat_buf; + int old_file_size; /* Open the old file, allocate a buffer of the right size, and read in the file contents. */ @@ -680,16 +681,16 @@ unexec (new_name, old_name, data_start, bss_start, entry_address) if (fstat (old_file, &stat_buf) == -1) fatal ("Can't fstat (%s): errno %d\n", old_name, errno); - old_base = malloc (stat_buf.st_size); - - if (old_base == 0) + /* We cannot use malloc here because that may use sbrk. If it does, + we'd dump our temporary buffers with Emacs, and we'd have to be + extra careful to use the correct value of sbrk(0) after + allocating all buffers in the code below, which we aren't. */ + old_file_size = stat_buf.st_size; + old_base = mmap (NULL, old_file_size, PROT_READ | PROT_WRITE, + MAP_ANON | MAP_PRIVATE, -1, 0); + if (old_base == (caddr_t) -1) fatal ("Can't allocate buffer for %s\n", old_name); -#ifdef DEBUG - fprintf (stderr, "%s: malloc(%d) -> %x\n", old_name, stat_buf.st_size, - old_base); -#endif - if (read (old_file, old_base, stat_buf.st_size) != stat_buf.st_size) fatal ("Didn't read all of %s: errno %d\n", old_name, errno); @@ -774,16 +775,11 @@ unexec (new_name, old_name, data_start, bss_start, entry_address) if (ftruncate (new_file, new_file_size)) fatal ("Can't ftruncate (%s): errno %d\n", new_name, errno); - new_base = malloc (new_file_size); - - if (new_base == 0) + new_base = mmap (NULL, new_file_size, PROT_READ | PROT_WRITE, + MAP_ANON | MAP_PRIVATE, -1, 0); + if (new_base == (caddr_t) -1) fatal ("Can't allocate buffer for %s\n", old_name); -#ifdef DEBUG - fprintf (stderr, "%s: malloc(%d) -> %x\n", new_name, new_file_size - new_base); -#endif - new_file_h = (ElfW(Ehdr) *) new_base; new_program_h = (ElfW(Phdr) *) ((byte *) new_base + old_file_h->e_phoff); new_section_h = (ElfW(Shdr) *) @@ -1202,8 +1198,8 @@ unexec (new_name, old_name, data_start, bss_start, entry_address) fatal ("Didn't write %d bytes to %s: errno %d\n", new_file_size, new_base, errno); - free (old_base); - free (new_base); + munmap (old_base, old_file_size); + munmap (new_base, new_file_size); /* Close the files and make the new file executable. */ -- 2.39.2