From: Shile Zhang shile.zhang@linux.alibaba.com
mainline inclusion from mainline-v5.6-rc1 commit 3c47b787b6516d2c3cbaa193fe13a83adbaaad1f category: feature bugzilla: NA CVE: NA
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The scripts/sortextable.c code has originally copied some code from scripts/recordmount.c, which used the same setjmp/longjmp method to manage control flow.
Meanwhile recordmcount has improved its error handling via:
3f1df12019f3 ("recordmcount: Rewrite error/success handling").
So rewrite this part of sortextable as well to get rid of the setjmp/longjmp kludges, with additional refactoring, to make it more readable and easier to extend.
No functional changes intended.
[ mingo: Rewrote the changelog. ]
Signed-off-by: Shile Zhang shile.zhang@linux.alibaba.com Acked-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: Josh Poimboeuf jpoimboe@redhat.com Cc: Masahiro Yamada yamada.masahiro@socionext.com Cc: Michal Marek michal.lkml@markovi.net Cc: linux-kbuild@vger.kernel.org Link: https://lkml.kernel.org/r/20191204004633.88660-2-shile.zhang@linux.alibaba.c... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com Reviewed-by: Jian Cheng cj.chengjian@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- scripts/sortextable.c | 119 +++++++++++++++--------------------------- scripts/sortextable.h | 11 ++-- 2 files changed, 48 insertions(+), 82 deletions(-)
diff --git a/scripts/sortextable.c b/scripts/sortextable.c index 55768654e3c6a..cd9762ba44674 100644 --- a/scripts/sortextable.c +++ b/scripts/sortextable.c @@ -22,7 +22,6 @@ #include <getopt.h> #include <elf.h> #include <fcntl.h> -#include <setjmp.h> #include <stdio.h> #include <stdlib.h> #include <string.h> @@ -51,61 +50,41 @@ #define EM_ARCV2 195 #endif
-static int fd_map; /* File descriptor for file being modified. */ -static int mmap_failed; /* Boolean flag. */ -static void *ehdr_curr; /* current ElfXX_Ehdr * for resource cleanup */ -static struct stat sb; /* Remember .st_size, etc. */ -static jmp_buf jmpenv; /* setjmp/longjmp per-file error escape */ - -/* setjmp() return values */ -enum { - SJ_SETJMP = 0, /* hardwired first return */ - SJ_FAIL, - SJ_SUCCEED -}; - -/* Per-file resource cleanup when multiple files. */ -static void -cleanup(void) -{ - if (!mmap_failed) - munmap(ehdr_curr, sb.st_size); - close(fd_map); -} - -static void __attribute__((noreturn)) -fail_file(void) -{ - cleanup(); - longjmp(jmpenv, SJ_FAIL); -} - /* * Get the whole file as a programming convenience in order to avoid * malloc+lseek+read+free of many pieces. If successful, then mmap * avoids copying unused pieces; else just read the whole file. * Open for both read and write. */ -static void *mmap_file(char const *fname) +static void *mmap_file(char const *fname, size_t *size) { - void *addr; + int fd; + struct stat sb; + void *addr = NULL;
- fd_map = open(fname, O_RDWR); - if (fd_map < 0 || fstat(fd_map, &sb) < 0) { + fd = open(fname, O_RDWR); + if (fd < 0) { perror(fname); - fail_file(); + return NULL; + } + if (fstat(fd, &sb) < 0) { + perror(fname); + goto out; } if (!S_ISREG(sb.st_mode)) { fprintf(stderr, "not a regular file: %s\n", fname); - fail_file(); + goto out; } - addr = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_SHARED, - fd_map, 0); + addr = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); if (addr == MAP_FAILED) { - mmap_failed = 1; fprintf(stderr, "Could not mmap file: %s\n", fname); - fail_file(); + goto out; } + + *size = sb.st_size; + +out: + close(fd); return addr; }
@@ -264,19 +243,18 @@ static void sort_relative_table(char *extab_image, int image_size) } }
-static void -do_file(char const *const fname) +static int +do_file(char const *const fname, void *addr) { - table_sort_t custom_sort; - Elf32_Ehdr *ehdr = mmap_file(fname); + table_sort_t custom_sort = NULL; + Elf32_Ehdr *ehdr = addr; + int rc = -1;
- ehdr_curr = ehdr; switch (ehdr->e_ident[EI_DATA]) { default: fprintf(stderr, "unrecognized ELF data encoding %d: %s\n", ehdr->e_ident[EI_DATA], fname); - fail_file(); - break; + return -1; case ELFDATA2LSB: r = rle; r2 = r2le; @@ -298,7 +276,7 @@ do_file(char const *const fname) || (r2(&ehdr->e_type) != ET_EXEC && r2(&ehdr->e_type) != ET_DYN) || ehdr->e_ident[EI_VERSION] != EV_CURRENT) { fprintf(stderr, "unrecognized ET_EXEC/ET_DYN file %s\n", fname); - fail_file(); + return -1; }
custom_sort = NULL; @@ -306,7 +284,6 @@ do_file(char const *const fname) default: fprintf(stderr, "unrecognized e_machine %d %s\n", r2(&ehdr->e_machine), fname); - fail_file(); break; case EM_386: case EM_X86_64: @@ -333,16 +310,15 @@ do_file(char const *const fname) default: fprintf(stderr, "unrecognized ELF class %d %s\n", ehdr->e_ident[EI_CLASS], fname); - fail_file(); break; case ELFCLASS32: if (r2(&ehdr->e_ehsize) != sizeof(Elf32_Ehdr) || r2(&ehdr->e_shentsize) != sizeof(Elf32_Shdr)) { fprintf(stderr, "unrecognized ET_EXEC/ET_DYN file: %s\n", fname); - fail_file(); + break; } - do32(ehdr, fname, custom_sort); + rc = do32(ehdr, fname, custom_sort); break; case ELFCLASS64: { Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr; @@ -350,21 +326,22 @@ do_file(char const *const fname) || r2(&ghdr->e_shentsize) != sizeof(Elf64_Shdr)) { fprintf(stderr, "unrecognized ET_EXEC/ET_DYN file: %s\n", fname); - fail_file(); + break; } - do64(ghdr, fname, custom_sort); + rc = do64(ghdr, fname, custom_sort); break; } } /* end switch */
- cleanup(); + return rc; }
int main(int argc, char *argv[]) { - int n_error = 0; /* gcc-4.3.0 false positive complaint */ - int i; + int i, n_error = 0; /* gcc-4.3.0 false positive complaint */ + size_t size = 0; + void *addr = NULL;
if (argc < 2) { fprintf(stderr, "usage: sortextable vmlinux...\n"); @@ -373,28 +350,16 @@ main(int argc, char *argv[])
/* Process each file in turn, allowing deep failure. */ for (i = 1; i < argc; i++) { - char *file = argv[i]; - int const sjval = setjmp(jmpenv); + addr = mmap_file(argv[i], &size); + if (!addr) { + ++n_error; + continue; + }
- switch (sjval) { - default: - fprintf(stderr, "internal error: %s\n", file); - exit(1); - break; - case SJ_SETJMP: /* normal sequence */ - /* Avoid problems if early cleanup() */ - fd_map = -1; - ehdr_curr = NULL; - mmap_failed = 1; - do_file(file); - break; - case SJ_FAIL: /* error in do_file or below */ + if (do_file(argv[i], addr)) ++n_error; - break; - case SJ_SUCCEED: /* premature success */ - /* do nothing */ - break; - } /* end switch */ + + munmap(addr, size); } return !!n_error; } diff --git a/scripts/sortextable.h b/scripts/sortextable.h index d4b3f6c40f027..5a62e94df678c 100644 --- a/scripts/sortextable.h +++ b/scripts/sortextable.h @@ -87,7 +87,7 @@ static int compare_extable(const void *a, const void *b) return 0; }
-static void +static int do_func(Elf_Ehdr *ehdr, char const *const fname, table_sort_t custom_sort) { Elf_Shdr *shdr; @@ -146,17 +146,17 @@ do_func(Elf_Ehdr *ehdr, char const *const fname, table_sort_t custom_sort) } if (strtab_sec == NULL) { fprintf(stderr, "no .strtab in file: %s\n", fname); - fail_file(); + return -1; } if (symtab_sec == NULL) { fprintf(stderr, "no .symtab in file: %s\n", fname); - fail_file(); + return -1; } symtab = (const Elf_Sym *)((const char *)ehdr + _r(&symtab_sec->sh_offset)); if (extab_sec == NULL) { fprintf(stderr, "no __ex_table in file: %s\n", fname); - fail_file(); + return -1; } strtab = (const char *)ehdr + _r(&strtab_sec->sh_offset);
@@ -190,7 +190,7 @@ do_func(Elf_Ehdr *ehdr, char const *const fname, table_sort_t custom_sort) fprintf(stderr, "no main_extable_sort_needed symbol in file: %s\n", fname); - fail_file(); + return -1; } sort_needed_sec = &shdr[get_secindex(r2(&sym->st_shndx), sort_needed_sym - symtab, @@ -206,4 +206,5 @@ do_func(Elf_Ehdr *ehdr, char const *const fname, table_sort_t custom_sort) #endif /* We sorted it, clear the flag. */ w(0, sort_done_location); + return 0; }